The proposed work involves phenomenological, ultrastructural, biochemical, and genetic studies of the motile events occurring in various stages in the life cycle of Physarum polycephalum. Characterization of plasmodial actin and myosin will continue with special focus on actin activation of myosin ATPase and its possible control by factors not tightly bound to the actomyosin complex. Isolation of actin and myosin from microplasmodia and amoebae already underway will proceed, drawing heavily on results obtained with the plasmodial proteins. Cinemicrographic analyses of the streaming and/or movement of micro-plasmodia and amoebae will be conducted, and attempts will be made to prepare glycerinated models of both; one purpose of the latter studies is to gain evidence as to the existence and nature of any calcium regulated control factors. Characterization of the amoebo-flagellate transformation will focus on efforts to a) gain better operational control of the process, b) describe the events occurring using both light and electron microscopy, c) analyze the biochemical changes taking place - in particular, the nature of any microtubular proteins involved, and d) select mutants with altered motility and/or ability to transform.